October 20, 2021, 01:24:20 PM
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Topic: How to standadize NaHCO3 using HCl  (Read 864 times)

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Offline aladin89

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How to standadize NaHCO3 using HCl
« on: June 01, 2021, 11:23:45 PM »
Hello everyone,
Im new to this group. I want to know titration method of standardization NaHCO3 using HCl.


Offline Borek

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Re: How to standadize NaHCO3 using HCl
« Reply #1 on: June 02, 2021, 03:13:49 AM »
Please read the forum rules. You have to show your attempts at answering the question/solving the problem to receive help, it is a forum policy.

This sounds like a classic acid/base titration. Check the endpoint pH to select the indicator
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline Elric82

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Re: How to standadize NaHCO3 using HCl
« Reply #2 on: June 02, 2021, 05:09:31 AM »
Hello everyone,
Im new to this group. I want to know titration method of standardization NaHCO3 using HCl.

Im assuming you have read the rules by now and know that an answer wont/cant be given.  But this can still be worked through.

So what do you know of titrations and molarity? Would you simply react a liquid with a solid, or would you make an aqueous solution?

Offline Asim

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Re: How to standadize NaHCO3 using HCl
« Reply #3 on: June 18, 2021, 04:19:05 PM »
A Two-Stage Reaction
When you add a hydrochloric acid (HCl) solution to a solution of sodium carbonate (Na2CO3), the hydrogen ion in HCl switches places with one of the sodium ions in Na2CO3 to produce sodium hydrogencarbonate, also known as sodium bicarbonate (baking soda), and sodium chloride (salt).

Na2CO3(aq) + HCl(aq) → NaHCO3(aq) + NaCl(aq)

Sodium hydrogencarbonate is basic, and it reacts with the HCl still in solution to produce sodium chloride, carbon dioxide and water.

NaHCO3(aq) + HCl(aq) → NaCl(aq) + CO2(g) + H2O(l)

Phenolphthalein is a good indicator for the first reaction because it responds to the pH change caused by the formation of sodium hydrogencarbonate. It is pink in basic solutions and turns colorless as soon as the solution becomes acidic. Methyl orange, on the other hand, responds to pH changes associated with the formation of NaCl, changing from yellow to red as the solution becomes more acidic. At neutrality, it is a distinct orange color


Offline javhert

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Re: How to standadize NaHCO3 using HCl
« Reply #4 on: July 01, 2021, 10:47:21 AM »
From experience doing water analyisis, HCl solutions are less stable for a long time (HCl slowly evaporates so the concentration decreases) than solid sodium bicarbonate. Usually carbonate salts are used to determine the concentration of HCl since those can be acquired at a high purity.

Assuming you are evaluating a batch of unknown NaHCO3, your best bet is to standardize HCl first against a high purity carbonate salt and then titrate the sample with it.

Offline KrXeRadon

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Re: How to standadize NaHCO3 using HCl
« Reply #5 on: October 06, 2021, 04:40:45 PM »
I assume you're suggesting a pH titration of a NaHCO3 sample using an indicator like phenophthalien. That will be an exercise in futility. Adding acid to bicarb will push the CO3-HCO3-CO2 equilibrium toward the right. The result will be CO2 in aqueaous solution, carbonic acid. The pH will constantly change until all the CO2 gasses out of solution.

The way to a standardized NaHCO3 solution is to weigh a solid sample of NaHCO3 of known purity on an analytical balance and dilute it in a volumentric flask.

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